<p> Plyometric Training on Unstable Surfaces 1</p><p>Tables and Legends:</p><p>Table 1 Pre- and post-test mean values, standard deviations, and relative differences in the Left- -Right-Hop (LRH), countermovement jump test (CMJT), hurdle drop jump test (HDJT), static balance Stork Test (ST), dynamic balance test (DBT), agility Hexagonal Obstacle Test (HOT), and an isometric leg extension strength test (ILES) for the training groups exercising on stable (STAB) and unstable (INST) surfaces. Single (*) and double (**) asterisks indicate α-error prob- abilities of 0.05 and 0.01 in the paired t-test for the pre-post differences for both groups separate- ly and for the F-tests, single (°) and double (°°) circles indicate α-error probability of 0.05 and 0.01 in the non-parametric Wilcoxon-test. In addition, F-values with effect size vales (partial η2) are listed for significant pre-post main ef- fects (Fm) and for the significant interactions of the pre-post factor and the group factor (Fx). Reliability estimates (ICC) were calculated through Cronbach’s α (internal consistency) across the three trials during pre-test measurements. </p><p>ICC STAB (n=13) INST (n=20) Age (y) 24.1 ± 4.6 24.1 ± 3.4 Height (cm) 179 ± 5.3 182 ± 5.2 Mass (kg) 75.8 ± 8.3 76.0 ± 8.9 LRH (s) pre 0.99 3.8 ± 0.5 3.8 ± 0.4 Left-Right-Hop post 3.8 ± 0.5 3.8 ± 0.5 %diff -0.1% + 0.3% CMJT (cm) pre 0.99 39.9 ± 4.3 35.3 ± 4.8 Countermovement Jump Test post 42.0 ± 6.0 40.1 ± 4.8 Fm = 28.1** (η2=0.47) Fx = 4.4* (η2=0.12) %diff +5.1% +14.5% ** °° HDJT (cm) pre 0.99 49.2 ± 6.7 44.2 ± 5.7 Hurdle Drop Jump Test post 51.3 ± 6.8 48.4 ± 6.3 Fm = 17.7 ** (η2=0.36) %diff +4.6% +9.8% * °° ST (s) pre 0.82 17.3 ± 12.8 10.5 ± 8.0 Static Balance Stork-Test post 15.2 ± 10.6 11.8 ± 6.6 %diff -1.0% +39.7 % DBT (s) pre 0.98 3.9 ± 0.8 3.8 ± 0.7 Dynamic Balance Test post 3.2 ± 0.5 3.1 ± 0.5 Fm = 61.5 ** (η2=0.67) %diff +15.9% * °° +18.4% ** °° HOT (s) pre 0.98 11.4 ± 1.2 10.9 ± 1.2 Agility Hexagonal Obstacle Test post 10.3 ± 1.2 9.9 ± 1.0 Fm = 57.1 ** (η2=0.65) %diff +9.7% * °° +8.3% ** °° ILES (kg) pre 0.98 162.9 ± 30 174.5 ± 36 Isometric Leg Extension Strength post 186.2 ± 42 194.9 ± 44 Fm = 12.3 ** (η2=0.29) %diff +14.7% ° +13.4% °</p>